On March 1, 2011, the Supreme Court of the United States issued its decision in Staub v. Proctor Hospital (No. 09-400). The Court held an employer is liable for the biased intentions of a supervisor who influences, but does not take, the ultimate adverse action against an employee. The Court confined its analysis to the Uniformed Services Employment and Reemployment Rights Act (“USERRA”) but noted that USERRA contains “motivating factor” language similar to that of Title VII and other federal workplace discrimination laws.

The Court based its decision on traditional tort and agency principles. The final decision-maker’s unbiased decision does not prevent the supervisor’s previous unlawful action from being the proximate cause of the harm, because “it is common for injuries to have multiple proximate causes.” Staub’s supervisors, Janice Mulally and Michael Korenchuk, intended to cause Staub’s dismissal and their actions formed the proximate cause of Staub’s ultimate termination by Linda Buck, an unbiased decision-maker.

The Court declined to establish an affirmative defense for the employer when its final decision-maker had conducted an independent investigation. In doing so, the Court refused to apply the Seventh Circuit’s definition of the “cat’s paw” as having a “singular influence” on the decision-maker. Thus, so long as the decision-maker relied on the biased supervisor’s action, with or without considering other factors, the employer will be held liable. To avoid liability in the face of an adverse action, the employer’s investigation must disclose reasons for the action that are independent of the biased supervisor’s motives.

The Court’s opinion specifically refused to address whether the same principles would apply to make an employer liable when a co-worker influences the ultimate decision-maker, as opposed to a supervisor exerting a similar influence.

Justice Scalia delivered the opinion of the Court, in which Chief Justice Roberts and Justices Kennedy, Ginsburg, Breyer, and Sotomayor joined. Justice Alito filed an opinion concurring in judgment, in which Justice Thomas joined. Justice Kagan took no part in the consideration or decision of the case.